I don't believe something can be 'a most important'... doesn't it defy the idea of a superlative adjective?
It can be, but in a different sense - when most means very, rather than its usual superlative sense. The register for this usage is kind of high, though, so it's not common. It's mostly used humorously these days.
If you google "a most" a bunch of examples pop up. I don't know if it's proper grammar, but I have heard it used. Admittedly 'the' would be more common.
Oh yes, having read mitStrudel's comment, I now remember seeing this 'a most urgent matter' and so on, meaning more like 'very'. If it's so, no, I wouldn't say that it's a translation. It really is superlative.
Ok, so let me see if I got this right. najwazniejsze is only for a very literal most - there can be none better. Using 'a' allows for something else to be at least equal if not better? I assume then that there would be a different Polish word to mean what "a most" would mean.
I don't think there's a way to say 'a most' in Polish. Other than just translating "very/really" important. "jedno z najważniejszych pytań" would be closest, but that's "one of the most important questions".
there can be a whole series of different problems to which all have a most important solution. A most important solution can and does exist if there are most important solutions to different things.
this translates to this most important question not this is the most important question
It kinda translates to both. Sometimes you can omit "jest" and the sentence still sounds perfectly fine.
"This most important question!" doesn't really seem like a probable thing to say... I don't see any other reports for it apart from your comment.
Also, this only 'could be' "This most important question!" because "pytanie" is neuter. For example, if you had "To mój pies!", that could only mean "This is my dog!", because "to" can't be a determiner here, it doesn't match "pies" grammatically".
This is a most important question, there is more of these questions This is the most important question, this is the most important of all questions 'Do you still love me?' Nothing can be more important.